Polyamines Metabolism and their Relation with Reactive Oxygen Species and other Cellular Molecules during Plant Interactions with Pathogens

Polyamines are considered as essential molecules for plant growth and development. They are also implicated in abiotic and biotic stress responses. The roles of polyamines in abiotic stress regulation have been well understood, whereas their roles in response to biotic stress are poorly characterized in plants. However, various recent reports have acknowledged that polyamines and their catabolism generated H O play important roles 2 2 during biotic stress in plants. Polyamines and polyamines dependent signalling mediate reactive oxygen species (ROS) scavenging as these molecules accumulate in response to biotic stress. Polyamine catabolism also results in generation of H O which act either by 2 2 directly killing the pathogens or by acting as signalling molecules that mediate defense responses in plants. The H O also interacts with the plant cell wall components and 2 2 provides strength to the cell wall after infection and wounding. Polyamine catabolism generated H O also play a role in signalling events post infection, which leads to 2 2 hypersensitive cell death. They also interact with calcium dependent signalling cascade, phytohormones and secondary metabolites and provide resistance to plants during biotic stress. In this review we discussed the possible roles of polyamines and polyamines catabolism generated H O and metabolites during plant host and pathogen 2 2 interactions.